Nginx+Keepalived雙主輪詢負載均衡
將兩臺LBServer（Nginx）分別新增VIP1與VIP2（Keepalived心跳監測），兩臺LBServer互為主從，共同提供服務，提高資源利用率。同時使用DNS管理系統（如Dnspod）做多條A記錄解析至對應的VIP1與VIP2，實現對兩臺Nginx的輪詢(負載均衡)，當一臺LBServer故障時，VIP會轉移到另一臺繼續提供服務，這裡配置Nginx+keepalived雙主高可用。
系統
兩臺Nginx
CentOS6.7 x86_64
兩臺Web
Ubuntu15.04 desktop
IP地址
Nginx1:192.168.15.132
Nginx2:192.168.15.133
VIP1:192.168.15.135
VIP2:192.168.15.136
Real1:192.168.15.128
Real2:192.168.15.130
部署整個環境用到的軟體為:
nginx-1.6.3.tar.gz
prce-8.38.tar.gz
zlib-1.2.8.tar.gz
①2臺Web主機（Ubuntu）上部署環境，安裝Nginx+PHP-FPM+MySQL
②分別在二臺Nginx負載均衡器上安裝Nginx，配置
安裝GCC編譯器等工具：
yum install -y gcc gcc-c++ autoconf automake libtool make openssl openssl-devel
安裝Nginx:
wget http://exim.mirror.fr/pcre/pcre-8.38.tar.gz
tar -zxvf pcre-8.38.tar.gz
cd pcre-8.38
./configure
make && make install
wget http://zlib.net/zlib-1.2.8.tar.gz
tar -zxvf zlib-1.2.8.tar.gz
cd zlib-1.2.8
./configure
make && make install
wget http://nginx.org/download/nginx-1.6.3.tar.gz
tar -zxvf nginx-1.6.3.tar.gz
./configure--prefix=/usr/local/nginx
--sbin-path=/usr/local/nginx/sbin/nginx
--conf-path=/usr/local/nginx/conf/nginx.conf
--pid-path=/usr/local/nginx/logs/nginx.pid \
--with-http_ssl_module \
--with-http_stub_status_module \
--with-http_gzip_static_module \
make&&makeinstall
注：查詢"./configure --help"相關模組，按需求指定啟用
Nginx.conf配置檔案，二個nginx負載均衡器的檔案一樣
user www-data www-data;
worker_processes 1;
error_log /usr/local/nginx/logs/error.log notice;
pid /usr/local/nginx/logs/nginx.pid;
worker_rlimit_nofile 51200;
events {
use epoll;
worker_connections 51200;
}
http {
include mime.types;
default_type application/octet-stream;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log logs/access.log main;
server_names_hash_bucket_size 128;
client_header_buffer_size 32k;
large_client_header_buffers 4 32k;
client_max_body_size 8m;
sendfile on;
tcp_nopush on;
server_tokens off;
keepalive_timeout 60;
fastcgi_connect_timeout 300;
fastcgi_send_timeout 300;
fastcgi_read_timeout 300;
fastcgi_buffer_size 64k;
fastcgi_buffers 4 64k;
fastcgi_busy_buffers_size 128k;
fastcgi_temp_file_write_size 128k;
gzip on;
upstream backend
{
server 192.168.15.128;
server 192.168.15.130;
}
server {
listen 80;
server_name 192.168.15.135;#Nginx2改為192.168.15.136
location / {
root html;
index index.php index.html index.htm;
proxy_redirect off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
#後端的Web伺服器可以通過X-Forwarded-For獲取使用者真實IP
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass http://backend;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
location /nginx_status {
stub_status on;
auth_basic "NginxStatus";
auth_basic_user_file /usr/local/nginx/htpasswd;
#allow 127.0.0.1;
#deny all;
}
location ~* \.(ini|docx|txt|doc|pdf)$ {
#禁止訪問文件性檔案
root /usr/share/nginx/html;
deny all;
}
location~.*\.(gif|jpg|jpeg|png|bmp|swf|js|html|htm|css)${
root/home/image;
proxy_storeon;
proxy_store_accessuser:rwgroup:rwall:rw;
proxy_temp_path/home/image;
if(!-e$request_filename){
proxy_passhttp://backend;
}
}
}
}
③在二臺Nginx上安裝及配置keepalived：
wget http://www.keepalived.org/software/keepalived-1.2.15.tar.gz
tar -zxvf keepalived-1.2.15.tar.gz
cd keepalived-1.2.15
./configure --sysconf=/etc/ --with-kernel-dir=/usr/src/kernels/2.6.32-573.8.1.el6.x86_64
make && make install
ln -s /usr/local/sbin/keepalived /sbin/
#這一步很重要，不執行ln -s會報錯“Starting keepalived: /bin/bash: keepalived: command not found”
servicekeepalivedstart
二臺Nginx上keepalived.conf配置如下，配置完成後分別servicekeepalivedstart啟動，檢測keepalived配置是否成功
Nginx1：
global_defs {
notification_email {
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id NGINX_VIP1
}
vrrp_script chk_http_port {
script "/usr/local/src/check_nginx_pid.sh"
interval 2 #（檢測指令碼執行的間隔）
weight 2
}
vrrp_instance VI_1 {
state MASTER
interface bond0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port #（呼叫檢測指令碼）
}
virtual_ipaddress {
192.168.15.135/24 broadcast 192.168.15.255 dev bond0 label bond0:1
}
}
vrrp_instance VI_2 {
state BACKUP
interface bond0
virtual_router_id 52
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port #（呼叫檢測指令碼）
}
virtual_ipaddress {
192.168.15.136/24 broadcast 192.168.15.255 dev bond0 label bond0:2
}
}
Nginx2：
global_defs {
notification_email {
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id NGINX_VIP2
}
vrrp_script chk_http_port {
script "/usr/local/src/check_nginx_pid.sh"
interval 2 #（檢測指令碼執行的間隔）
weight 2
}
vrrp_instance VI_1 {
state BACKUP
interface bond0
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port #（呼叫檢測指令碼）
}
virtual_ipaddress {
192.168.15.135/24 broadcast 192.168.15.255 dev bond0 label bond0:1
}
}
vrrp_instance VI_2 {
state MASTER
interface bond0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port #（呼叫檢測指令碼）
}
virtual_ipaddress {
192.168.15.136/24 broadcast 192.168.15.255 dev bond0 label bond0:2
}
}
以下是針對nginx狀態進行檢測的指令碼，第一次nginx服務死掉時會重新啟動，如果Nginx無法正常啟動，則殺掉keepalived程序
vim /usr/local/src/check_nginx_pid.sh
#!/bin/bash
A=`ps -C nginx --no-header |wc -l`
if [ $A -eq 0 ];then
/usr/local/nginx/sbin/nginx
if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
killall keepalived
fi
fi
配置完畢，測試停掉其中一臺的任何服務，不影響整個系統的運作。通過DNS管理系統輪詢VIP1與VIP2，實現Nginx的負載均衡｡
轉載於:https://my.oschina.net/HeAlvin/blog/552875